System error. Please re-try your action

Our users reported running into "System error. Please re-try your action. If you continue to get this error, please contact the administrator" this morning when they tried to login into Oracle SaaS application. At this moment the users are not encountering the error but would like to get a root cause and if there is any resolution to ensure this does not happen in the future. We looked at multiple KM documents that had same error messages but they did not have any definitive root cause or resolution.